Year	Percent
1996	3.4737
1997	4.049
1998	2.688
1999	4.7955
2000	7.6153
2001	5.0066
2002	2.6995
2003	4.3828
2004	3.5432
2005	4.9734
2006	2.6925
2007	2.9958
2008	3.6347
2009	3.7918
2010	4.1609
2011	7.4679
2012	6.632
2013	7.3886
2014	8.568
2015	8.1395
2016	7.4545
2017	7.2502